Connecting two blood vessels, anastomosis, is an important surgical technique for reconstructive, therapeutic and cosmetic surgery. The gold standard of anastomosis is manual suturing of the two blood vessels in a side to side, end to end or end-to-side configuration. Although it is generally desirable to shorten the length of any surgical procedure, this is especially important in coronary bypass surgery, in which a patient is usually attached to a heart-lung machine and his heart is often stopped.
In addition to manual suturing of blood vessels, other methods of attaching two blood vessels are known, including, staples and anastomosis rings. PCT publications WO 97/40754 and WO 97/28749, the disclosures of which are incorporated herein by reference, describe staplers for coronary bypass surgery, wherein a graft is connected on one of its ends to the aorta and at its other end to an occluded coronary artery, distal to the occlusion. In this type of surgery, the anastomosis is sealed by stapling the graft to the aorta, while pressing both aorta and graft against an anvil. In one publication, the anvil is inserted into the aorta for the stapling and then removed, possibly by taking the anvil apart. In the other publication, the end of the graft is everted over a ring-shaped anvil, so that the anvil is outside of the blood vessel at all times.
Recently, bypass surgery has been performed using minimally invasive (key-hole) surgery. In this type of surgery, a small hole is made in the chest, instead of cracking open the ribs, and the mammary arteries (e.g., LIMA, RIMA) are used for bypass grafts. The suturing and/or stapling is performed using tools, for example as described above.
An even less invasive type of surgery requires no opening of the chest at all, rather, one or more catheters are introduced into the blood vessels using a precutaneous approach. PCT publications WO 97/27898, WO 97/13471 and WO 97/13463 and their priority documents, namely U.S. application 60/010,614, 60/005,164, 08/730,327 and 08/730,496, the disclosures of which are incorporated herein by reference and termed the “Transvascular Applications”, describe method and apparatus for precutaneous treatment of arterial occlusions. Two main methods are taught in these applications. In one method, a tunnel is excavated within tissue (outside the vessel) from one side of the occlusion to the other side of the occlusion, and a stent or a stent/graft may be placed within the tunnel. In another method, a conveniently located vein or graft is attached to the occluded vessel and two side-to-side anastomosis are created between the occluded vessel and the vein or graft bypassing the occlusion. The distal and proximal portions of the vein are closed in one of a variety of manners. The connection between the vein and the artery may be by welding the two blood vessels, or by using one of a variety of connectors that are suggested. One of the disclosed connectors comprises two springs separated by a short segment of a possibly unstented graft. The springs have the form of an inverted funnel, so that the two blood vessels are urged together. Where there is a spacing between the blood vessels, various techniques and/or devices are suggested for stopping the surrounding tissue from compressing the connection between the vein and the artery. One of the purposes of the various types of connectors is to maintain the two blood vessels near each-other, either in contact or by compressing tissue between them, presumably so no blood will leak from the connection between the connector and the blood vessels.
In a TIPS procedure, a stent is placed into a passage precutaneously forced, opened or excavated between a portal vein and a hepatic vein. As in some of the embodiments described in the previous paragraph, the relative location of the blood vessels is maintained by the existence of relatively solid tissue surrounding and between the two blood vessels. Thus, there is no requirement that each of the connections between an end of the connector and the respective blood vessel to which it is attached, be, of itself, completely leak-proof.
In WWW publication “http://me210abc.stanford.edu/94–95/projects/Pfizer/Spring/1.html”, available March 1998, the disclosure of which is incorporated herein by reference, a method is described for reducing the complexity of performing a bypass surgery. In this method, a graft is precutaneously brought to the aorta and pushed out of an incision in the aorta near a site of a bypass surgery. A keyhole opening is made in the chest to bring a tool to suture or staple the graft to the aorta and to the coronary which is to be bypassed.
The attachment of a graft to a coronary vessel is especially problematic, inasmuch as the vessel is typically diseased and, being thin, it is easily damaged.
Many people suffer from blockages of the peripheral blood vessels. A typical treatment procedure in these cases is to perform a bypass of the abdominal aorta, of the femoral artery or perform a femoral-popliteal bypass.